This measure is traditionally dedicated to suicide prevention at bridges. However, a fenced bridge also prevents falling accidents. It may be effective against young people who illegally climb tall structures to practice “skywalking”.

GRPanti-trespass panels can be fitted to bridge parapets to prevent suicide or to deter people from climbing onto bridge parapets. Such a trial is to be carried out in the UK.

Suicide rate clearly increased in the period when the barriers were removed, compared to the rate when barriers were in place (Beautrais et al., 2009): Barriers in place (1991-1995): 5 suicides; barriers removed (1997-2002): 19 suicides; barriers reinstalled (2003-2006): 0 suicides. Removal of barriers was followed by a fivefold increase in the number and rate of suicides from the bridge. Since the reinstallation of barriers there have been no suicides from the bridge.

In Bern suicides by jumping from the Muenster Terrace stopped completely after the installation of a safety net of 4 metres wide, seven metres below the top level (Reisch & Michel, 2005).

After securing a bridge in the Canton of Zug (Switzerland), there have been no more suicides by jumping during the past 3 years (Hepp et al., 2012).

Following the interventions, there was an 86% reduction in jumping suicides per year at the sites in question (95% CI 79% to 91%). There was a 44% increase in jumping suicides per year at nearby sites (95% CI 15% to 81%), but the net gain was a 28% reduction in all jumping suicides per year in the study cities (95% CI 13% to 40%). Structural interventions at ’hotspots’ avert suicide at these sites. Some increases in suicide are evident at neighbouring sites, but there is an overall gain in terms of a reduction in all suicides by jumping (Pirkis et al., 2013).

Survivors of jumps from heights (not on the railway) report that this type of fencing measure might have prevented them from their suicide attempt (NIMH, 2006). Effectiveness and the aesthetics of barriers at bridges have apparently been considered at the University of California in Berkeley (see NIMH, 2006).

The theory behind restricting access to means (at hotspots) is that it may ‘buy time’ for the individual to reconsider his or her actions, particularly in situations where these actions are associated with impulsivity or ambivalence (Cox et al., 2013).

If a particular feature of the environment encourages or allows suicide it can be ethical to try to prevent access to that means of suicide, even if there is a risk of substitution (Beautrais, 2007).